This invention relates to a pump and more particularly to pumping apparatus in which there is a counterflow of liquid through the pump.
The present invention is directed to a pump mechanism which is particularly useful in replacing current centrifical pumps which use a motor driven impeller within a close fitting housing. Also, the present invention is of particular utility in operations currently using centrifugal pumps to pump liquids containing large quantities of foreign matters, such as slurries. A particular problem with such pumps is the clogging thereof by the matter being carried by the liquid which is often in the form of silt, sewage, chemicals, foods, particulates, etc. Typical uses of such pumps are in mining operations dredging silt from harbors, canal digging, laying of pipes, laying of cable through water, industrial purposes, sewage systems, etc.
When pumping liquids having abrasive foreign substances therein in relatively high quantities, the centrifical pumps may have an extremely short life because of wear and tear from the foreign substances, or the over filling of spaces within the pump by the foreign substances eventually clogging the pump. To counteract such wear and tear, centrifical pumps may be provided with heavy liners which are expensive initially and particularly when they have to be replaced or repaired. With the present invention, large open spaces in the pump casing and the absence of direct impact against an impellor blade alleviate such wear or clogging problems.
Another problem with current centrifical pumps is the development of sufficient total head which includes a suction lift which the vertical distance from the level of the pump inlet to the pump, and additionally, the discharge lift which is the vertical distance between the pump and pump discharge outlet. The commonly used centrifically pumps for slurries, or the like, are driven at low rpm, particularly where the suction lift is relatively high. In such pumps, an increase in the pump speed actually results in a reduction of the suction lift produced by the pump so that the suction lift can not be improved by increased pump speed. With the present invention, however, increase of suction lift may be obtained by increased speed of the rotating member of the pump.
For a number of centrifugal pumps the suction lift usually very limited and most often limited to atmospheric pressure without the use of special valves or other equipment. When the desired suction lift is greater than this, a vertical pump is often resorted to. The vertical pump uses a long shaft extending from a motor located above the body of liquid and with the long shaft extending downwardly to the submerged pump housing in which is mounted the rotating impeller. The long shaft and the bearings for supporting the shaft constitute limitations on the pump. The pump shaft is necessarily heavy and wastes energy to rotate the heavy shaft. The length of the shaft can not be excessive without being very expensive and necessitating expensive bearings and other supporting equipment. Another form of submersible pump has the motor submersed with the pump housing into the liquid and this requires oil or other material in the pump motor and the use of seals and other expensive devices to prevent the intrusion of liquid into the motor. Additional problems with submersible pumps having submerged motors is that of preventing electrical shock or short circuit. Repairs or replacement of the pump is expensive because it is located at considerable depth. With the present invention large suction lifts may be obtained without shafts or submerging the pump motor.
Accordingly, a general object of the present invention is to provide a new and improved pump.
Another object of the invention is to provide a new and improved pump for handling slurries containing a high percentage of foreign substances without clogging or damaging the pump.
A further object of the invention is to provide an eddy current pump in which a vortex column of liquid is discharged from the center of the pump inlet pipe resulting in a concentrated area of reduced pressure at the pump inlet to cause the ambient surrounding liquid and foreign substances, if any, to be drawn upwardly about the downwardly traveling vortex column in the manner of an eddy current.